Conventionally, a cell module, which is one form of electric storage apparatus, is provided as the power source for equipment. The cell module includes a plurality of single cells which are electrically connected with each other, and a holder for holding the plurality of single cells.
The plurality of single cells are aligned in a first direction. Adjacent single cells are disposed with a predetermined space therebetween in the first direction. As a result of this, an inter-cell air passage which passes through in a second direction orthogonal to the first direction is formed between single cells.
There are various types of holders. As one of those types, for example, a holder including a holder body which is formed so as to be able to accommodate a plurality of single cells is provided (for example, see Japanese Patent Laid-Open No. 2009-181896).
The holder body includes one pair of column groups which are disposed on both sides in the first direction of the accommodated plurality of single cells. Each of the column groups is made up of a plurality of column portions which are opposed only to a single cell located at one end in the first direction. The plurality of column portions extend in a third direction orthogonal to the first and second directions and are spaced apart from each other in the second direction. As a result of this, air vent portions which are opened in the first direction are formed side by side in the second direction.
According to the cell module having the above described configuration, it is reported that by circulating gas in the inter-cell air passage and circulating gas through air vent portions, the plurality of single cells can be cooled thereby suppressing an excessive temperature rise of the single cells associated with charging and discharging.
However, the column portion opposed to the single cell located at one end in the first direction extends in the third direction orthogonal to the direction of gas circulation (the second direction). Therefore, the column portions impair smooth circulation of gas in the second direction. That is, the presence of the column portions necessarily increases the pressure loss of the gas circulating in the second direction in the air vent portions. Thus, in the cell module having the above described configuration, there may be a case that the single cell located at one end in the first direction is not effectively cooled.
Further, this type of problem similarly arises in, without being limited to single cells, electric storage devices such as capacitors.